Gear change for bicycle or like machine

ABSTRACT

The invention relates to a gear change for bicycle or like machine comprising two rollers linked together by a support, movement of said unit being controlled cross-wise to the free wheel of the bicycle or like machine by means of a control wire, and the support linking the two rollers being made up of two parts articulated one on the other, a spring being positioned between these two parts in order to keep the two rollers constantly separated from each other.

1151 3,677,103 July 18, 1972 United States Patent Huret et al.

[54] GEAR CHANGE FOR BICYCLE OR [56] References Cited UNITED STATES PATENTS LIKE MACHINE [72] Inventors: Jacques Andre Huret; Roger Henri l-luret,

74/217 B ....74/2l7 B 3,453,899 7/1969 Tartuania et al. ....................74/217 B 3,364,762 1/1968 both of 60, Avenur Felix Fame, Namerre, 3,364,763 1/1968 I 'l-Iaute de Seine, France 22 Filed: Dec. 28, 1970 Primary Examiner-C. J. Husar [2]] Appl. No.:

Attorney-Donnelly, Mentag & Harrington ABSTRACT The invention relates to a gear change for bicycle or like machine comprising two rollers linked together by a support, movement of said unit being controlled cross-wise to the free wheel of the bicycle or like machine by means of a control 521 U.s.C| 51 1111.01

l6h 9/00 wire, and the support linking the two rollers being made up of [58] Field of two parts articulated one on the other, a spring being positioned between these two parts in order to keep the two rollers constantly separated from each other.

6 Clains, 4 Drawing figures PATENTEDwusmn 3 577103 SHEET-10F?) INV ENMKS JACQ ANDRE HUKET PATENTEB JUL 18 1912 3,577; 103

snm 3 0F 3 Fig 4 I/VI/f/V TOPS JACQUES ANDRE HURfT ROGER Hf/VR/ H0957 GEAR CHANGE FOR BICYCLE OR LIKE MACHINE SUMMARY OF THE INVENTION The invention relates to a gear change for cycle, such as bicycle, motor cycle or like machine, allowing a considerable increase in the gear change ratio.

Gear changes for bicycles, composed basically of two small wheels kept apart at a constant distance by small supporting plates, are already known. These two rollers and their support move cross-wise to the free-wheel drive of the back wheel of the bicycle under the action of a wire, so that the chain passing over the two rollers may be brought into the plane of one or other of the free wheel pinions. When the chain passes from a pinion with a given diameter to a pinion with a different diameter, smaller or greater, the result is a difference in the effective length of the chain, difference which is absorbed by the unit comprising rollers and support plates pivoting around a spindle fitted with a return spring.

This pivoting of the rollers and their support plates is generally on a spindle identical with that of one of the rollers, the other roller always being in a position such that it keeps the driving chain under constant tension under the action of the return spring.

However, in these known gear changes the maximum variation in the gear change ratio, that is to say the maximum difference between the free wheel pinions, is limited since the unit comprising rollers and support plates can absorb only a relatively small difference in the length of the driving chain. I

For this reason, up to now the difference in diameter between the largest and smallest free wheel pinion or the difference in diameter between the toothed pedal-gear faceplates has remained relatively small, thus limiting possibilities for the bicycle depending on whether it is traveling on a slope or on a flat road.

For this purpose, this invention relates to a gear change for bicycle or like machine, comprising two rollers linked together by a support, movement of said unit being controlled cross-wise to the free wheel of the bicycle or like machine by means of a control wire, gear change wherein the support linking the rollers is made up of two parts articulated one on the other, a spring being positioned between these two parts in order to keep the two rollers constantly separated from each other.

In accordance with another characteristic of the invention, the unit comprising rollers and their support, made up of two parts articulated one on the other, is mounted on a spindle identical with that of one of the rollers, the distance between this roller and the articulating spindle of the support parts being shorter than that between the other roller and the articulating spindle of the support parts.

In accordance with another characteristic, stops are fitted to restrict articulation of the two support parts articulated one on the other and to prevent the articulating spindle of the two support parts coming into alignment with the spindles of the two rollers.

BRIEF DESCRIPTION OF THE DRAWINGS The invention is illustrated as a non-limiting example in the accompanying drawings, in which:

FIG. 1 is a diagrammatic perspective view of a method of producing a gear change in accordance with the invention.

FIG. 2 is an elevation view of the unit comprising rollers and supports for a chain in an initial position.

FIG. 3 shows the unit in FIG. 2 in an intermediary gear change ratio.

FIG. 4 shows the unit in FIGS. 2 and 3 in a position corresponding to the use of the smallest available diameters of pinion and face-plate.

DESCRIPTION OF THE PREFERRED EMBODIMENT The object of this invention is, consequently. to enable appropriate working of a derailleur gear change even though the free wheel pinions may be of very different diameters and,

also, for it to be possible to use several pedal-gear face-plates of very different diameters.

The object of the gear change in accordance with the invention is therefore to absorb an important length of bicycle chain, which becomes unnecessary following the use of smaller diameter free wheel pinions and pedal-gear faceplates.

FIG. 1 thus shows the two arms 1,, 1 of the rear fork of a bicycle on which is mounted the free wheel 2 with five speed ratios.

The driving chain 3 of this bicycle passes over one or other of these pinions.

The gear change in accordance with the invention is fixed to lug 4 of arm 1, in a way which is itself known.

This gear change is made up of a lug 5 on which is fixed, so that it can be adjusted, a second lug 6. This second lug 6 supports on its lower end a unit shaped like a parallelogram that can be distorted, made up of arms 7, 8, 9 and 6,, this latter arm 6, being formed by an extension of lug 6. It should, however, be noted that this parallelogram-shaped unit could be replaced by other devices, themselves known and filling the same role. For example, this distortable parallelogram could be replaced by a sliding horizontal rod pushed by a spring.

The articulations of the various arms of the distortable parallelogram are made up of screws 10 and lug 9 of this parallelogram has an extension 9, on which is mounted a pivoting unit comprising tension rollers 11 and 12 and their support 13, so that this unit is controlled in translation, cross-wise to the free wheel.

This group 11, 12, 13 is mounted on extension 9,'by means of a screw 14 which receives in succession a plate 15 fitted with a raised edge forming a stop 15,, a return spring 16, then support 13 and roller 11.

In accordance with the invention, support 13 is in two parts, each having two arms 17,, 17 18,, 18 articulated one on the other by means of a spindle, in this case formed by connecting screw 19.

A return spring 20, of which one end 20,, is hooked to arm 17 and the other 20 fits into a hole in arm 18,, is positioned around this screw 19 and between arms 17,, 18, and 17 18 The roller 12, rotating on spindle 21, is positioned at the edge of the raised edges of arms 18,, 18,.

Given this construction, it will be seen that the distance separating spindle or screw 14 and 21 is variable, given the articulation of screw 19.

In addition, the return spring 20 positioned between arms 17 and 18 constantly tends to separate spindle 21 from spindle 14 by making it pivot around spindle 19 in the direction of arrow F (see FIG. 2).

Likewise, spring 16 placed around spindle 14 is engaged at one end with hook 22 (see FIG. 2), while it is immobilized by its other end on extension 9,. This spring also tends to make the group comprising roller 11, 12 and support 13 pivot constantly, so that articulating spindle 19 tends to move at practically the same level as spindle l4 and behind it in relation to the direction in which the bicycle advances.

For an extreme gear change position, rollers l1, l2 and support 13 occupy the position illustrated in FIG. 2, and this position corresponds to the largest diameters of the free wheel pinion and pedal-gear face-plate, the distance separating spindles l4 and 21 being the shortest possible.

When the rider operates traction wire 23, he distorts the parallelogram 7, 8, 9, 6, in order to move rollers l1, 12 in In this position, it will be seen that the distance separating spindles 14 and 21 has increased in order to compensate for the difference in the length of chain necessary, and to keep this chain at constant tension despite the variations in the free wheel pinion diameters used and, possibly, despite the variation in pedal-gear face-plate diameters used.

Lastly, when the smallest free wheel pinion and pedal-gear face-plate diameters are used, articulated support 13 moves into the position shown in FIG. 4 and it will be seen that, for this position, spindle 19 is situated slightly above the line passing through spindles 14 and 21, and that the lower edge of roller 11 is situated above the lower edge of roller 12. This is made possible by stops provided to limit the action of spring 16 controlling the swing of arms 17,, 17 around spindle 14 and to limit the swing of arms 18,, 18 around articulating spindle 19.

In effect, a stop edge 17 is formed on arm 17,; in the position illustrated in FIG. 4, this stop edge 17;, comes into contact with a stop 18 on arm 18,. Likewise, in this position stop limits the opening of spring 16, one end of which is engaged on hook 22.

With the gear change in accordance with the invention, it will be seen that it is possible to use pinions or gear-change face-plates of very different diameters, given that the difference in the circumference of these pinions or face-plates can be completely absorbed. in effect, the capacity for absorption of the difference in necessary chain length corresponds closely to the maximum of twice the distance separating spindles l4 and 21 in their most distant position (FIG. 4).

In this construction, it will also be noted that arms 18 and 18 are slightly longer than arms 17,, 17 so that spindles 14, 21 and 19 occupy a relative position such that springs 16 and 20 have a maximum action whatever the pinion or face-plate used, this relative position of spindles 14, 21 and 19 also being such that roller 11 and 12 absorb the minimum length of chain when the pinion and face-plate used are the largest, and the maximum length of chain when the pinion and face-plate are the smallest.

ln effect, it will be noted, in accordance with FIG. 2, that spindle 21 is slightly in front of spindle 14, while spindle 19 is slightly below this spindle 14. On the other hand, in accordance with FIG. 4, spindle 19 is slightly above spindle l4 and slightly above the line through spindles 21 and 14, while the lower edge of roller 11 is slightly above the lower edge of roller 12.

It should be understood that the invention is not limited to the embodiment described and represented above; from this it is possible to foresee other methods and other embodiments which in no way exceed the scope of the invention.

What is claimed is:

1. A gear change unit for a bicycle having a free wheel, comprising two rollers linked together by a support, movement of said unit being controlled cross-wise to the free wheel of the bicycle by means of a control wire, gear change wherein the support linking the rollers is made up of two parts articulated one on the other, a spring being positioned between these two parts in order to keep the two rollers constantly separated from each other.

2. A gear change in accordance with claim 1, wherein the return spring connecting the two parts of the support articulated one on the other is hooked onto each of these parts by each end.

3. A gear change in accordance with claim 1, wherein the unit comprising rollers and their support, made up of two parts articulated one on the other, is mounted on a spindle identical with that of one of the rollers, the distance between this roller and the articulating spindle of the support parts being shorter than the distance between the other roller and the articulating spindle of the support parts.

4. A gear change in accordance with claim 3, wherein a spring is positioned around the pivoting spindle of the unit comprising rollers and support, in order constantly to place the articulating spindle of the two parts of the support behind the roller whose spindle is identical with the pivoting spindle of the unit.

5. A gear change in accordance with claim 4, wherein stops are fitted to restrict articulation of the two support parts articulated one on the other and to prevent the articulation spindle of the two support parts coming into alignment with the spindles of the two rollers.

6. A gear change in accordance with claim 5, wherein one stop is provided near to the pivoting spindle for the unit comprising rollers and support, in order to limit the action of the return spring controlling the pivoting of this unit and to ensure that the lower edge of the roller, whose spindle is identical with the units pivoting spindle, is always at a higher level than the lower edge of the other roller. 

1. A gear change unit for a bicycle having a free wheel, comprising two rollers linked tOgether by a support, movement of said unit being controlled cross-wise to the free wheel of the bicycle by means of a control wire, gear change wherein the support linking the rollers is made up of two parts articulated one on the other, a spring being positioned between these two parts in order to keep the two rollers constantly separated from each other.
 2. A gear change in accordance with claim 1, wherein the return spring connecting the two parts of the support articulated one on the other is hooked onto each of these parts by each end.
 3. A gear change in accordance with claim 1, wherein the unit comprising rollers and their support, made up of two parts articulated one on the other, is mounted on a spindle identical with that of one of the rollers, the distance between this roller and the articulating spindle of the support parts being shorter than the distance between the other roller and the articulating spindle of the support parts.
 4. A gear change in accordance with claim 3, wherein a spring is positioned around the pivoting spindle of the unit comprising rollers and support, in order constantly to place the articulating spindle of the two parts of the support behind the roller whose spindle is identical with the pivoting spindle of the unit.
 5. A gear change in accordance with claim 4, wherein stops are fitted to restrict articulation of the two support parts articulated one on the other and to prevent the articulation spindle of the two support parts coming into alignment with the spindles of the two rollers.
 6. A gear change in accordance with claim 5, wherein one stop is provided near to the pivoting spindle for the unit comprising rollers and support, in order to limit the action of the return spring controlling the pivoting of this unit and to ensure that the lower edge of the roller, whose spindle is identical with the unit''s pivoting spindle, is always at a higher level than the lower edge of the other roller. 